Biomedical subjects

Katherine Hansen

Publications and source records attributed to Katherine Hansen.

3 recordsLinked to original sources

PubMed2006

A case study of an emerging community-based early hearing detection and intervention program: part II. Team building with otolaryngologists and pediatricians using a survey approach.

PURPOSE: Physicians are vital team members of early hearing detection and intervention programs (EHDIPs), particularly in encouraging parents to comply with recommendations for follow-up services for their infants in universal newborn hearing screening programs (UNHSPs). This study describes a survey approach to help audiologists partner with otolaryngologists and pediatricians in EHDIPs. METHOD: We developed and mailed a 19-item questionnaire to all 12 otolaryngologists and 66 pediatricians potentially involved in a community-based EHDIP. The questionnaire assessed respondents' demographic data and knowledge of, experiences with, and attitudes toward the service-delivery continuum of UNHSPs. RESULTS: The overall response rate was 45%; all 12 otolaryngologists responded (100%; data from 7 were analyzed), and 23 pediatricians responded (34.8%; all were analyzed). Generally, they were positive toward and knowledgeable about UNHSPs and believed that (a) parent/infant bonding is unaffected by screening, (b) hearing reevaluations following medical services are important, (c) audiologists perform their role adequately, (d) it is important that hearing losses be identified and interventions begun before infants reach 6 months of age, (e) UNHSPs deserve funding, and (f) their role is important, but the physicians also wanted improvements in parent education and referral/follow-ups. CONCLUSION: The survey method was effective in identifying participating physicians' informational needs and attitudes toward UNHSPs, and in designing outreach programs for them.

Attitude of Health Personnel↗

PubMed2004

Microarray expression profiling in melanoma reveals a BRAF mutation signature.

We have used microarray gene expression profiling and machine learning to predict the presence of BRAF mutations in a panel of 61 melanoma cell lines. The BRAF gene was found to be mutated in 42 samples (69%) and intragenic mutations of the NRAS gene were detected in seven samples (11%). No cell line carried mutations of both genes. Using support vector machines, we have built a classifier that differentiates between melanoma cell lines based on BRAF mutation status. As few as 83 genes are able to discriminate between BRAF mutant and BRAF wild-type samples with clear separation observed using hierarchical clustering. Multidimensional scaling was used to visualize the relationship between a BRAF mutation signature and that of a generalized mitogen-activated protein kinase (MAPK) activation (either BRAF or NRAS mutation) in the context of the discriminating gene list. We observed that samples carrying NRAS mutations lie somewhere between those with or without BRAF mutations. These observations suggest that there are gene-specific mutation signals in addition to a common MAPK activation that result from the pleiotropic effects of either BRAF or NRAS on other signaling pathways, leading to measurably different transcriptional changes.

Amino Acid Substitution↗

PubMed2003

Estrogen receptor-dependent genomic responses in the uterus mirror the biphasic physiological response to estrogen.

The physiological responses of the rodent uterus to acute estrogen (E) dosing can be divided into early and late events. Examples of early responses include increased RNA transcription, hyperemia, and water imbibition 2 and 6 h following E administration respectively, whereas later responses include cycles of DNA synthesis and mitosis of epithelial cells beginning 10 and 16 h after E. The development of estrogen receptor (ER) knockout (ERKO) mice, combined with microarray technology, has allowed us to design a genomic approach to study the acute response of the rodent reproductive tract to E. To determine whether early and late biological responses are correlated with altered regulation of a single set of genes or distinct sets of genes characteristic of early and late responses, uterine RNA was obtained from ovariectomized mice that were treated with vehicle or with estradiol for 2 h (early) or 24 h (late). Samples were also prepared from identically treated mice that lacked either ERalpha (alphaERKO) or ERbeta (betaERKO) to address the relative contributions of the ERs in the uterine responses. Microarray analysis of the relative expression of 8700 mouse cDNAs indicated distinct clusters of genes that were regulated both positively and negatively by E in the early or late phases as well as clusters of genes regulated at both times. Both early and late responses by the betaERKO samples were indistinguishable from those of WT samples, whereas the alphaERKO showed little change in gene expression in response to E, indicating the predominant role for ERalpha in the genomic response. Further studies indicated that the genomic responses in samples from intermediate time points (6 h, 12 h) fall within the early or late clusters, rather than showing unique clusters regulated in the intermediary period. The use of this genomic approach has illustrated how physiological responses are reflected in genomic patterns. Furthermore, the identification of functional gene families that are regulated by E in the uterus combined with the utilization of genetically altered experimental animal models can help to uncover and define novel mechanisms of E action.

Animals↗